The present invention relates to a device for handling a load, particularly a load immersed in a liquid, by means of a shaft having a polygonal cross-section permitting both a precise angular positioning of the shaft and a displacement thereof along its axis without vibration.
Countries having nuclear power stations for the generation of electricity are attempting to obtain the lowest possible kWh costs. For this purpose, the fuels must be used to a maximum. The non-destructive inspection and control of the development of the health of the canning of said fuel makes it possible to decide whether their use can be continued. It is advantageous to be able to carry out this control on site. The irradiated fuel elements are stored in ponds, the water ensuring the biological protection and heat exchange of the residual power. The inspection of a rod requires it to pass in front of sensors, whilst remaining immersed. The investigation of incipient faults requires high sensitivity levels on the part of the detection equipment. The knowledge of the position of the faults requires not only a passage, but also a rotation of the rod.
At present, shafts are guided in several different ways in the devices used for handling fuel elements. It is possible to use two parallel cylindrical guides along which travels a connection mechanism fixed to the shaft. Other systems use one or two guides provided with a longitudinal groove, in which travels a key, which is fixed to the shaft. The guide bars can also be in the form of grooved shafts permitting the sliding of a member connected rigidly to the shaft, said member being provided with grooves which cooperate with those of the guide bar. It is also possible to use slide guides in various forms, along which travel members integral with the shaft. All these systems can be equipped with ball bearings or ball guides. However, these devices have the disadvantage of not permitting a random orientation of the shaft relative to a fixed chassis.